If you are holding a lot then i suggest you buy hardware wallet, pay a little bit for a far better security for your investment. Also it's hard to crack a bitcoin wallet as long as your computer isn't contaminated by malware or you enter the seed in phising site. If somehow your btc gets hacked, then nothing can be done about it, you can't get it back and you can only blame yourself for not securing it well enough.

Always careful do not let anyone know your private key. Do not connect your devices on public places. Do not click any suspicious link to avoid any leaked in you account.

Maybe you shouldn't say that you have a lot of BTC.

ye, that's the first thing you should not do, saying "hey guys, i have a lot of money and i'm scared of thief, what should i do?"
Be wise and smart, never ever give out this kind of information in primis then, take all the precaution to keep your coins safe (you got already many great advices in this topic).
Hardware wallet it's the way to go, even better if you can put it in a bank safe but really, do not shout that you have a lot of money, there are a lot of greedy people around.

And being afraid will help you accomplish what? Nothing at all. Instead of being afraid,  you should start doing your research. It's good that OP did.

To OP:
I know that you've been hearing a lot of things about people having their wallets hacked. But it's all because of their own negligence. It's possible that their computer was already hacked even before they have generated their wallet. It's possible that someone (in his home) has access to his computer and is also a bitcoin user and they got the bitcoins. Remember, in your own house is most likely where you'd find the thief (in life in general, not just in bitcoins).

If you are not hacked by now, then probably you are not hacked at all and you're just overthinking things. Because if you were the hacker, you wouldn't wait for a little long when you hacked a bitcoin address because the person might sell out some of his coins. You're not going to wait for that person to have more bitcoins, you just hack it right away.

If you got hacked, you can't do anything. The only indication that you got hacked is when your bitcoins are already gone, right? You and I know that bitcoin's transactions are not reversible and that doesn't change even when you have a lot of bitcoins.

there is nothing impossible nowadays hackers are everywhere.... but if you holding huge amount of bitcoins use wallet that you hold the private key or
use offline wallet.

Hackers have nothing to worry about, as long as you take care of your keys, don't click on the links from strangers, and those suspicious emails, don't click. Bitcoin is more than a few wallets to store, so it will be safe

If you have a decent or huge amount of bitcoins and you want to still use online wallets, the use those with 2 factor authentication. Make sure to keep your private key secured and stay away from suspicious sites. But the better choice would be to use a hard wallets like trezor.

Unfortunately many users report that they are hacked and that their coins are stolen,and most of them use online wallets-but recently many users report they desktop (Electrum) wallet are hacked.Only way to pretect BTC is to move it from hot wallets of any type and create paper wallet/cold storage-but most effective way is hardware wallet since you can use it every day and your coins will be safe.

What I would recommend to anyone who wants to protect coins is to check some of hardware wallets on this Black Friday,I just got e-mail that Ledger Nano S price will go down by 21%.